Particle Therapy in the Third Millennium: Current Status and Future Outlook

Abstract

Robert Wilson’s recognition of the therapeutic potential of the physical characteristics of protons formed the foundation of particle therapy. He proposed the use of charged particles for the radiotherapy of cancers in 1946 [1]. Although the clinical promise of particle therapy was considered undisputable, there were only intermittent developments and limited adoption of this modality until the end of the twentieth century, presumably because of the high cost of establishing and operating clinical particle therapy facilities. Most of the particle treatments during that period were carried out at facilities designed for physics experiments. Notable among these facilities were Lawrence Berkeley National Lab (LBNL) (1955–1992, protons); MGH-Harvard Cyclotron (1961–2001, protons); LBNL (1975–1992, heavy ions); HIMAC, NIRS, Japan (1994–, Carbon ions); Paul Scherrer Institute (PSI), Switzerland (1996–, protons); and GSI, Germany (1997–, Carbon ions). Of these, PSI is the only facility that has employed scanning beams and intensity-modulated proton therapy (IMPT) from the inception. Loma Linda University was the first to establish a hospital-based proton therapy facility in 1990, followed by NCC, Japan, in 1998.